Electric switch



1934' H. H KNOWLES ET AL 1,978,365

ELECTRIC SWITCH Filed Dec. 7, 1931 3 Sheets-Sheet 2 INVENTO 44 7 7/ e Oct. 23, 1934. H H. KNOWLES r AL 1,978,365

ELECTRIC SWITCH Filed Dec. 7, 1931 3 Sheets-Sheet 3 IN VEN TORS Patented Oct. 23, 1934 1,97s,3ss

ELECTRIC swn'cn Barry 11. Knowles, Birmingham, and. George N. Lemmon, HomewoodsAla.

Application December 7, 1931, Serial No. 579,596 14 Claims. (01.200-48) The object of our invention is to provide a high voltage switch which shall be easily operable, in

spite of the size and weight of' the moving members.

This object is accomplished mainly by having a jaw contact which releases the, blade with a minimum amount of friction, by' counter-balancing the long blade effectively, and by having a means for readily adjusting each long stack of insulators so that it is true about its axis.

Referring to the drawings, Fig. 1 shows a single unit of the assembled switch; Figs. 2 and 3' show respectively a plan view and elevation of the collars used for adjusting the insulators; Fig. 4 shows a cross section through the counter-balancing spring and adjacent parts; Fig. 5 shows the jaws and blade in closed position; Fig. 6 is a view of these parts just as the blade is leaving the jaws; and Fig. 7 shows a plan view of the braces between two of the insulators. Figs. 8, 9, 10, 11,- and 12 are perspective views of some parts which are shownpartially in section, and similarly numbered, in Fig. 4. I

Upon a base 1 are mounted two stationary insulators 2, 3 and one rotatable insulator 4. It is customary for high voltage insulators to be made up of a number of separate units bolted together into stacks as shown. Individual irregularities in .the various units often will throw such astack 30 with the proper coordination of the machined parts on top of the insulators. This tends also to produce excessive friction.

Under each insulator stack we use two wedge shapedcollars 5, 5,-which are capable of being independently revolved completely around the outside of the bolts. This can be done when the bolts are merely loosened.

With one thick and one thin side together, no change in alignment is made by the collars. With two thick and two thin sides together, a maximum change in alignment is produced. Since both collars are movable, any desired amount of realignment up to the maximum can be made in any direction, without removing the bolts, and therefore without risk of the heavy insulators falling.

, The projections 6, 6', 6' can be tapped with a hammer, and so make adjustments even with the weight of the insulators borne by the collars.

The switch blade 7 is shown in Fig. 1 in closed pomtion; in the open position the blade is at '7'..

-The hingecasting 8 revolves about the pivot 9,

, being actuated by therotatable insulator 4, the

crank 10, and the connecting bar 11.

66 Acoflspflng13,atoneendwiththe out of accurate alignment and thereby interfere being contracted by closing the switch.

movable 8, and at the other end with the stationary member 13; the last turn at each end of the spring fits over the collar portion of the member with which it engages and therefore the whole central portion of the spring is free to function without developing friction between these coils and any other member. A roller bearing 14 reduces the friction where thepart 8' of the movable casting 8 surrounds the stationary pivot 9.- The stationary member 13 has an extended portion 15 which serves to re-- enforce the pivot 9, and the projections 16 serve to turn 13 when desired. A sleeve 17 is locked to 13 by the bolt 18., A projection 19 engages with v a hole 19' in the base fitting 20. A sleeve 21 is. sli tted at one place and can be contracted by means of the bolt 22 so that it touches part of the outside of the. coil spring 12 when the spring is in normal position; this prevents any expansion of the coils at this portion of the spring. As 7 usually adjusted, the coil spring is contracted and acts to counter balance the weight of the switch blade when it is near the closed position. As the blade is raisedthe tension on the spring di-. minishes and it ceases when the blade is almost vertical. I

Further motion of the blade towards the fully opened position '1' tends to expand the spring 1 which then acts to check the momentum of the: mow'ng blade. It is desirable that this retarding motion increase rapidly, so that the spring shall act as a cushion stop for the blade in its open position; but theentire length of the spring gives too gradual an increase. The sleeve 21, by preventing expansion of part of the spring, ves the desired retarding action of a short spring as the switch reaches the open position, while still retaining the proper gradual counterbalancing action when the entire length of the spring is ,5

The switch blade '7 has a flattened end 23 which engages with the jaws. jaws consist of a pair of flexible brushes 24, each attached to the inside of a rockable housing 25 which is held by the pivot 26-to the stationary support 2'1. Suit able flexible conductors, not shown, make permanent connection between the brushes 24'and the main line terminal 28.

Thehousings25areshapedsothattheyact as a guide for-the entering blade 23, and a projection 29 on each housing enables the blade to bring theihousing into closed position as the blade closes. When closed as in Fig. 5, the brushes m'einpositivecontactwiththesidesofthe biadaandthenastheswitchisqienedthe brushes lift with the blade and as the housings rock about the pivots 26 the brushes move outwardly, leaving the blade disengaged as shown in Fig. 6.

This action has to overcome only-the friction about the pivots 26, and since these are under the housing they are easily kept in good operating condition. The amount of motion of each housing is limited by the shape of the support 27 and springs 30 can be used to bias the housings towards either the open position or the closed position.

The crank 10 is fixed to the insulator 4 and as 4 rotates the crank 10 and its connecting link 11 open or close the switch-blade '7 in the wellknown manner.

It is desirable that the braces 31 between the insulators 3, 4 shall be rigid and substantial. It is also necessary'to have the steady-bearing 32 in exact alignment with the long bearing 35 which supports the insulator 4. Otherwise severe friction may develop. To meet these requirements the braces 31 are placed to form the triangular support shown in plan view in Fig. '7, and each brace has a right and left thread by which its length may be changed any amount desired without affecting the length or position of the other brace.

The various adjustments make it easy to assemble the different parts regardless of irregularities in individual insulators, so that they operate with minimum friction.

We claim:

1. In an electric switch, a stationary base, in sulators mounted thereon by bolts, switch'members supported by the insulators, and a pair of.

tapered collars between the stationary base and one of the insulators, all portions of the collars being outside of the area which contains the bolts.

2. In an electric switch, a stationary base, insulators mounted thereon by bolts, switch members supported by the insulators, and a tapered collar below one of the insulators, all portions of said collar being outside of the area which contains the bolts.

3. In an electric switch, a stationary base, insulators mounted thereon by bolts, switch members supported by the insulators, and a tapered collar under one of the insulators, all portions oi, the collar being outside of the area which con-- tainsthe bolts and having an engageable projectibn which extends radially outwards.

.4.'In an electric switch, a movable pivoted arm, a torsional spring connected therewith, and meansto stress the spring in contraction and in expansion, respectively, at each end 01' the travel of the arm.

5. In an electric switch, a movable pivoted arm, a spring connected therewith, and-capable or being stressed in opposite directions, together with means to restrain part 01' the spring irom functioning when it is stressed in one of the said directions.

6. In an electric switch, a-movable blade, a pair of jaw contacts cooperable therewith, said jaw contacts comprising two spaced pivots, a hollow crank-member movably supported upon each pivot, and a spring contact member attached to the inside of each hollow crank-member.

7. In an electric switch, a movable blade, a pair of jaw contacts cooperable therewith, said jaw contacts comprising two spaced pivots, a hollow crank-member movably supported upon each pivot, and a spring contact member attached to the inside of each hollow crank-mem her, the said crank-members being arranged to form a guide for the blade as it closes.

8. In an electric switch, a hinged conducting blade, insulated means to open or close the blade, and a pair of jaw contacts cooperable with the swing end of the blade, the said jaw contacts comprising two spaced pivots, a hollow conducting guide member movably mounted above each of the said pivots and operable to guide the blade when closing, and a spring contact member secured to each of the said hollow guide members.

9 In an electric switch, a movable blade, a pair of bell-cranks cooperable with the blade, an arm on each bell-crank operable by the weight of the blade and. in electrical contact with it, and a flexible-contact member upon the other arm of each bell-crank, and operable to make strong pressure contact with the blade as the bell cranks are rotated to the closed position.

10. In an electric switch a movable blade, a pair of bell crank lever carriers cooperable therewith, a flexible contact member borne by each carrier and operable by the weight of the blade upon an arm of the carrier to effect strong pressure contact against the blade.

12. In an electric switch, a movable blade, a

pair 01' contact members cooperable therewith, a

pair of bell-crank carriers supporting the said contact members, means to bias the contact members entirely clear of the blade, and abutments on the carriers operable by the blade to rotate the contact members into full contact with the blade.

14. In an electric switch, a movable blade, a. pair of contact members cooperable therewith. a pair of fbell-crank carriers supporting the said contact members, means to bias the contact members entirely clear or the blade, and abutments on the carriers operable by the blade to rotate the contact members into full contact with the blade, the said bell-crank carriers also acting to guide the movable blade when closing. 

